If such ‘foreign recognition’ was actually necessary, then please answer one simple question:
Which foreign “country” recognized the very first sovereign nation to ever exist?
;>)
The modern concept of the nation-state can be traced to the Peace at Westphalia (1648, I believe). So, whatever countries existed at the time and met the generally accepted requirements of statehood that were set down at that time recongized each other simultaneously.
If the CSA had defeated the Union and obtained recognition as a sovereign nation, then it would have met the requirements of nationhood.